Up until very recently, when doing a search or using a filter, you could click on a work item in the results and it would open in the full page. You could then use shortcut keys like 'j' and 'k' or click the Up/Down arrows to walk through each item one at a time. There was also a Back button to return to the search/filter results.
Now issues open in a sidebar and I can see no way to return to the old behavior. Has that been removed?
Instead, you can click the pop out button to open the issue in a new tab, but that doesn't allow you to move up and down the results list. You can also expand the size of the sidebar to half the page, but that is a much smaller work area than the full page. Finally, you can use shortcut keys like 'j' and 'k' to move up and down the list, but the results still take up half the page.
I've seen in a search for a solution there used to be a third button near the popout and close sidebar buttons that switched back to full page but that is not currently available on our system.